The goal of our study is to identify serologic markers that complement alpha fetoprotein (AFP) and its core- fucosylated analog (AFP-L3) in the detection of hepatocellular carcinoma (HCC) at a treatable stage. We and others have shown that major re-distribution of protein N-glycoforms occurs at the premalignant stage of liver cirrhosis. Our latest studies show that high mannose, core- and outer arm- fucosylated glycoforms of specific glycopeptides increase in HCC. These glycoforms are associated with liver secreted glycoproteins and are detectable in serum. In this study, we analyze liver secreted glycoproteins carrying these HCC specific N- glycan modifications by newly developed LC-MS-MRM targeted quantification methods. This is done because AFP and ultrasonography detect only approximately 60% of HCC cases and additional markers are needed to improve sensitivity of screening for this malignancy with continuously increasing incidence. Our data suggests that quantification of specific glycoforms of specific glycoprotein peptides offers the highest diagnostic accuracy. The optimized glycosidase assisted LC-MS-MRM methods allow, for the first time, targeted validation of the site specific glycopeptide marker candidates. Defining clinically applicable markers of HCC has potentially far-reaching consequences for disease management and patient health. Our study is expected to generate new hypotheses on the functional impact of protein glycosylation on the development of cancer and to stimulate new line of cancer detection research.